1. Technical Field
The present invention relates to a monofocal photographing lens assembly. More particularly, the present invention relates to a compact monofocal photographing lens assembly applicable to electronic products.
2. Description of Related Art
In recent years, the applications of an optical lens system are getting wider, especially in vehicle image system, image security system, internet video, mobile device, and compact camera. The image sensor of a conventional optical lens system is typically a CCD (Charge-Coupled Device) sensor or a CMOS (Complementary Metal-Oxide Semiconductor) sensor. As the advanced semiconductor manufacturing technologies have allowed the pixel size of the sensors to be reduced and compact optical lens system have gradually evolved toward the field of higher megapixels, there is an increasing demand for optical lens system featuring better image quality.
A conventional optical lens system with a large field of view mainly adopts lens element with negative refractive power near an object side, and adopts lens elements with positive refractive power near an image side, thus an inverse telephoto structure is formed for obtaining a larger field of view, such as a four-element optical lens system disclosed in U.S. Pat. No. 7,446,955.
Although other conventional optical lens systems with five-element lens structure such as the ones disclosed in U.S. Pat. No. 8,248,713 enhance image quality and resolving power, these optical designs still reside with unsolved problems. Since the outer diameter of each lens element of the conventional optical lens system has dramatic variation in geometry, it is not favorable for assembling the lens elements so as to decrease manufacturing yield rate, and the difficulty in lens barrel design also increases. As demands on vehicle image system, image security system, and internet video device are increasing, there exits a need on a monofocal photographing lens assembly with large field of view, excellent image quality, simple design, and high manufacturing yield rate.